Motor

ABSTRACT

A motor includes a rotor, a stator, a housing, a bus bar assembly, a cover fixed to the housing, and a circuit board. The bus bar assembly includes a bus bar, a wiring member, and a bus bar holder. The bus bar holder includes a main body portion, a connector portion, and a connection terminal holding portion. The cover directly or indirectly contacts a second side of the main body portion. The wiring member includes a circuit board connection terminal fixed to the connection terminal holding portion and an external power-supply connection terminal. At least one other portion of the wiring member is located closer to a second side of the motor than the external power-supply connection terminal.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese PatentApplication No. 2014-201410 filed on Sep. 30, 2014 and is a ContinuationApplication of PCT Application No. PCT/JP2015/069676 filed on Jul. 8,2015. The entire contents of each application are hereby incorporatedherein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present disclosure relates to a motor.

2. Description of the Related Art

One example of conventional motors has a stator equipped with a bus bar.For example, the motor includes a bus bar electrically connected to astator, and a bus bar holder holding a wiring member electricallyconnected to the hall IC. In order to prevent water, oil, or the likefrom flowing into the motor, the space between a housing (cover) and abus bar holder is sealed.

In the above-mentioned motor, the bus bar is connected to the stator bysoldering or the like, and the wiring member is connected to the hall ICby soldering or the like. In this case, when a portion contacting acover within the bus bar holder is deformed by heat caused by solderingor the like, a gap between the cover and the bus bar holder occurs suchthat sealability between the cover and the bus bar holder is reduced. Asa result, it is preferable that the above connection is carried out at aspecific position spaced apart from the portion contacting the coverwithin the bus bar holder.

However, if the number of electronic components mounted to the motor isincreased so as to improve responsiveness or the like, a circuit boardincluding the electronic components is easily mounted to the motor.However, in the above-mentioned structure, an outer edge of the circuitboard is likely to be located close to the contact portion between thecover and the bus bar holder. As a result, when the wiring member isconnected to the circuit board, the bus bar holder may be deformed byheat.

SUMMARY OF THE INVENTION

In accordance with one preferred embodiment of the present invention, amotor includes a rotor including a shaft with a center on a center axisextending in one direction from a first side of the motor to a secondside of the motor, a stator enclosing the rotor and rotating the rotorabout the center axis, a cylindrical housing holding the stator, a busbar assembly including a surface facing the first side of the motor andopposing the housing, and a circuit board disposed in the bus barassembly and opposing an inner surface of the bus bar assembly in aradial direction which is perpendicular to the center axis. The bus barassembly includes: a wiring member electrically connecting an externalpower supply to the circuit board, and a bus bar holder that holds thewiring member. The bus bar holder includes: a cylindrical main bodyportion, and a connector portion that protrudes from the main bodyportion toward a radially outer side of the center axis. The wiringmember includes: an external power-supply connection terminal providedin the connector portion to be electrically connected to the externalpower-supply, and a circuit board connection terminal that iselectrically connected to the circuit board. At least one other portionof the wiring member is located closer to the second side of the motorin the one direction than the external power-supply connection terminal.

The above and other elements, features, steps, characteristics andadvantages of the present invention will become more apparent from thefollowing detailed description of the preferred embodiments withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view illustrating a motor according to apreferred embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view illustrating themotor according to a preferred embodiment of the present invention.

FIG. 3 is a perspective view illustrating a bus bar assembly accordingto a preferred embodiment of the present invention.

FIG. 4 is a plan view illustrating the bus bar assembly according to apreferred embodiment of the present invention.

FIG. 5 is a partially enlarged cross-sectional view illustrating anotherexample of the motor according to a preferred embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Motors according to preferred embodiments of the present invention willhereinafter be described with reference to the attached drawings.Further, the scope of the present invention is not limited to thefollowing preferred embodiments, but may be arbitrarily changed withinthe technical spirit of the present invention. To easily understand eachcomponent in the following drawings, an actual structures, and a scaleof each structure, the number of structures, etc., may be different.

In the drawings, an X-Y-Z coordinate system is provided as anappropriate three-dimensional (3D) orthogonal coordinate system. In theX-Y-Z coordinate system, a direction parallel to the axial direction(one direction) of a center axis J shown in FIG. 1 will hereinafter bereferred to as a Z-axis direction. A direction parallel to alongitudinal direction of a bus bar assembly 60 shown in FIG. 1, thatis, the left-and-right direction of FIG. 1, is referred to as an X-axisdirection. A direction parallel to a width direction of the bus barassembly 60, that is, a direction perpendicular to both the X-axisdirection and the Z-axis direction, is referred to as a Y-axisdirection.

In the following description, a positive side of the Z-axis direction(+Z side, a second side) will hereinafter be defined as ‘rear side’ anda negative side of the Z-axis direction (−Z side, a first side) willhereinafter be defined as ‘front side.’ It is to be understood that thedescriptions of the rear side and the front side are used forexplanation only, and they do not limit location relation or directionof the actual motor, members, and the like. unless otherwise explained,a direction parallel to the center axis J (Z-axis direction) is simplyreferred to as ‘axial direction,’ a radial direction having its centeron the center axis J is simply referred to as ‘radial direction,’ and acircumferential direction having its center on the center axis J, thatis, the axial circumference of center axis J (θZ direction), is simplyreferred to as ‘circumferential direction.’

Further, herein, descriptions such as being axially extended do not onlyrefer to a case of strictly being extended in the axial direction(Z-axis direction), but it may also include the other case of beingextended in a direction inclined at less than about 45° relative to theaxial direction, for example. Also, descriptions such as being radiallyextended do not only refer to a case of strictly being extended in theradial direction, that is, the direction perpendicular to the axialdirection (Z-axis direction), but it may also include a case of beingextended in a direction inclined at less than about 45° relative to theradial direction, for example.

FIG. 1 is a cross-sectional view illustrating a motor 10 according to apreferred embodiment of the present invention. The motor 10 according tothe present preferred embodiment is a brushless motor. As illustrated inFIG. 1, the motor 10 preferably includes a housing 21, a cover 22, arotor 30 including a shaft 31, a stator 40, a first bearing 51, a secondbearing 52, a controller 70, a bus bar assembly 60, and a plurality ofO-rings. The plurality of O-rings preferably includes a front sideO-ring 81 and a rear side O-ring 82.

The rotor 30, the stator 40, the first bearing 51, and the oil seal 80are accommodated into the housing 21. The housing 21 is opened towardthe rear side (+Z side). An end of the front side (−Z side) of the busbar assembly 60 is inserted into the opening of the housing 21. The busbar assembly 60 holds the second bearing 52. The first bearing 51 andthe second bearing 52 support both sides of the axial direction (Z-axisdirection) of the shaft 31.

The cover 22 covers at least a portion of the rear side (+Z side) of thebus bar assembly 60. The cover 22 is fixed to the housing 21. The cover22 preferably includes a cylindrical portion 22 a, a cover portion 22 b,a front surface 22 c of the cover, and a rear side flange portion 24.The controller 70 is located between the second bearing 52 and the cover22. The front side O-ring 81 is located between the bus bar assembly 60and the housing 21. The rear side O-ring 82 is located between the busbar assembly and the cover 22. The above-mentioned components willhereinafter be described in greater detail below.

The housing 21 is preferably a cylindrical or substantially cylindricalmember, and holds the stator 40 and the first bearing 51. In a preferredembodiment of the present invention, the housing 21 preferably has amulti-stepped cylindrical shape or a substantially multi-stepped shapewith open ends on both sides. In this preferred embodiment, a materialof the housing 21 is, for example, metal. In more detail, it ispreferred that a material of the housing 21 is, for example, aluminum,iron alloy, or the like.

The housing 21 preferably includes a front side flange portion 23, a busbar assembly insertion portion 21 a, a stator holding portion 21 b, afront bearing holding portion 21 c, and an oil seal holding portion 21d. The front side flange portion 23, the bus bar assembly insertionportion 21 a, the stator holding portion 21 b, the front bearing holdingportion 21 c, and the oil seal holding portion 21 d are disposed in adirection from the rear side (+Z side) to a front side (−Z side) alongthe axial direction (Z-axis direction). That is, in the housing 21, thefront side flange portion 23 is preferably disposed at a rearmost sideand the oil seal holding portion 21 d is preferably disposed at afrontmost side. Each of the bus bar assembly insertion portion 21 a, thestator holding portion 21 b, the front bearing holding portion 21 c, andthe oil seal holding portion 21 d has a concentric cylindrical orsubstantially cylindrical shape. A diameter of the above members arereduced in the order of the bus bar assembly insertion portion 21 a, thestator holding portion 21 b, the front bearing holding portion 21 c, andthe oil seal holding portion 21 d.

The front side flange portion 23 extends from the end of the rear side(+Z side) of the bus bar assembly insertion portion 21 a toward aradially outer side. That is, the housing 21 includes a housing flangeportion 23 at the end of the rear side. The bus bar assembly insertionportion 21 a encloses an end of a front side (−Z side) of the bus barassembly 60 from the radially outer side of the center axis J. In otherwords, at least a portion of the end of the front side (−Z side) of thebus bar assembly 60 is disposed in the bus bar assembly insertionportion 21 a. That is, the end of the front side of the bus bar assembly60 is disposed in the housing 21.

An outer surface of a stator 40 (preferably an outer surface of a coreback portion 41, to be described later) is fitted into an inner surfaceof the stator holding portion 21 b. Accordingly, the stator 40 is fixedto the housing 21. The front bearing holding portion 21 c holds thefirst bearing 51. In this preferred embodiment, the inner surface of thefront bearing holding portion 21 c preferably is fitted into the outersurface of the first bearing 51. The oil seal 80 is held in the oil seatholding portion 21 d.

The rotor 30 preferably includes a shaft 31, a rotor core 32, and arotor magnet 33. The shaft 31 has its center on the center axis J whichextends in one direction (Z-axis direction). According to this exemplarypreferred embodiment, the shaft 31 is a cylindrical or substantiallycylindrical member. Further, the shaft 31 may be a solid member or as ahollow cylindrical member. The shaft 31 is rotatably supported aroundthe axis (in ±θZ direction) by the first bearing 51 and the secondbearing 52. The end of the front side (−Z side) of the shaft 31protrudes to the outside of the housing 21. In the oil seal holdingportion 21 d, the oil seal 80 is disposed around the axis of the shaft31.

The rotor core 32 is preferably a cylindrical or substantiallycylindrical member. The rotor core 32 is fixed to the shaft 31 whileenclosing the shaft 31 around the axis (in the θZ direction). In moredetail, the rotor core 32 preferably includes a through-hole whichpenetrates axially through the rotor core 32. At least a portion of theshaft 31 is disposed within the through-hole of the rotor core 32. Theshaft 31 is fixed to the rotor core 32 by, for example, press-fitting,adhesion, or the like. The rotor magnet 33 is fixed to an outer surfacealong an axis circumference of the rotor core 32. In more detail,according to this exemplary preferred embodiment, the rotor magnet 33preferably has an annular or substantially annular shape. The outersurface of the rotor core 32 faces the inner surface of the rotor magnet33. The rotor magnet 33 is fixed to the rotor core 32 by, for example,an adhesive, or the like. Further, the shape of the rotor magnet 33 isnot necessarily annular. The rotor magnet 33 may be defined by aplurality of magnets arranged on an outer circumferential surface of therotor core 32 in a circumferential direction. The rotor core 32 and therotor magnet 33 rotates integrally with the shaft 31.

The stator 40 preferably has a cylindrical or substantially cylindricalshape. The rotor 30 is located in the stator 40. In other words, thestator 40 encloses the rotor 30 around the axis (in the θZ direction).The rotor 30 may relatively rotate around the center axis J with respectto the stator 40. The stator 40 preferably includes a core back portion41, a plurality of teeth portions 42, a plurality of coils 43, and aplurality of bobbins 44. According to this exemplary preferredembodiment, the core back portion 41 and the teeth portion 42 is astacked steel plate in which a plurality of electromagnetic steel platesare stacked.

The core back portion 41 may have a cylindrical or substantiallycylindrical shape. Preferably, the shape of the core back portion 41 isconcentric with the shaft 31. The plurality of teeth portions 42 aredisposed on an inner surface of the core back portion 41. Each teethportion 42 extends from the inner surface of the core back portion 41toward a radially inner side (that is, toward the shaft 31). Preferably,the teeth portions 42 are arranged at equal or substantially equalintervals in the inner surface of the core back portion 41 in thecircumferential direction.

Preferably, the bobbin 44 is a cylindrical or substantially cylindricalmember. Each bobbin 44 is respectively mounted on one of the teethportions 42. Preferably, the bobbin is defined by at least two membersengaged from an axial direction. Each coil 43 is disposed in each bobbin44. Each coil 43 is provided preferably by winding a conductive wire 43a about a bobbin 44. Further, as the conductive wire 43 a, a circularwire or a flat wire is preferably used.

The first bearing 51 is disposed at a front side (−Z side) of the stator40. The first bearing 51 is held by the front bearing holding portion 21c. The second bearing 52 is disposed at the rear side (+Z side) oppositeto the front side of the stator 40. The second bearing 52 is held by arear bearing holding portion 65 of a bus bar holder 61 which will bedescribed later.

The first bearing 51 and the second bearing 52 support the shaft 31.According to this exemplary preferred embodiment, each of the firstbearing 51 and the second bearing 52 is a ball bearing. However, thetype of the first bearing 51 and the second bearing 52 is notparticularly limited to the above bearing type. For example, differentkinds of bearings such as a sleeve bearing and a fluid hydraulic bearingmay also be used. Further, the type of bearing of the first bearing 51may be different from that of the second bearing 52.

The oil seal 80 preferably is an annular or substantially annularmember. The oil seal 80 is mounted in the oil seal holding portion 21 daround the axis (in the θZ direction) of the shaft 31. In more detail,the oil seal 80 is disposed in the oil seal holding portion 21 d. An endof an axial lower portion of the shaft 31 penetrates through thethrough-hole of the oil seal 80. The oil seal 80 is disposed between theoil seal holding portion 21 d and the shaft 31. Therefore, the oil seal80 may prevent water, oil, etc., from infiltrating from a gap betweenthe oil seal holding portion 21 d and the shaft 31 into the housing 20.The oil seal 80 is preferably made of, for example, a resin material.However, a configuration and a material of the oil seal 80 are notlimited thereto, and therefore an oil seal of different kinds ofconfigurations and materials may also be used.

The controller 70 controls driving operations of the motor 10. Thecontroller 70 preferably includes the circuit board 71, a rotatingsensor 72, a sensor magnet holding member 73 a, and a sensor magnet 73b. That is, the motor 10 includes the circuit board 71, the rotationsensor 72, the sensor magnet holding member 73 a, and the sensor magnet73 b.

The circuit board 71 is disposed on an extending line of the rear side(+Z side) of the shaft 31. The circuit board 71 is disposed between thesecond bearing 52 and the cover 22 in the axial direction (Z-axisdirection). The circuit board 71 includes a circuit board rear surface71 a located at the rear side and a circuit board front surface 71 blocated at the front side (−Z side). The circuit board rear surface 71 aand the circuit board front surface 71 b define a main surface of thecircuit board 71. That is, the circuit board front surface 71 b and thecircuit board rear surface 71 a intersect with the center axis J(Z-axis). In this preferred embodiment, the main surface of the circuitboard 71 is preferably perpendicular or substantially perpendicular tothe center axis J (or Z-axis). The circuit board rear surface 71 a facesthe cover front surface 22 c.

The circuit board 71 is supported by the end of the rear side (+Z side)of a plurality of circuit board support portions 67 to be describedlater. At least one side of the main surface of the circuit board 71 isprovided with a printed wiring (not shown). The circuit board 71outputs, for example, a motor driving signal, etc.

The sensor magnet holding member 73 a is an annular member. A hole at acenter of the sensor magnet holding member 73 a is fitted with a smalldiameter of the end of the rear side (+Z side) of the shaft 31.Accordingly, the position of the sensor magnet holding member 73 a isdetermined on the basis of the shaft 31. Preferably, the sensor magnetholding member 73 a is fixed to the shaft 31 by press-fitting, adhesion,etc. The sensor magnet holding member 73 a may rotate along with theshaft 31.

The sensor magnet 73 b preferably has an annular or substantiallyannular shape. An N pole and an S pole of the sensor magnet 73 b arealternately disposed in the circumferential direction. The sensor magnet73 b is fitted on an outer circumferential surface of the sensor magnetholding member 73 a. In more detail, at least a portion of the sensormagnet 73 b comes in contact with the outer circumferential surface ofthe sensor magnet holding member 73 a. Therefore, the sensor magnet 73 bis fixed to the sensor magnet holding member 73 a. As a result, thesensor magnet 73 b is disposed at the circumference (±θZ direction) ofthe shaft 31 at the rear side (+Z side) of the second bearing 52 suchthat the sensor magnet 73 b is able to rotate along with the shaft 31.

At least one rotation sensor 72 is preferably mounted on the frontsurface 71 b of the circuit board. The rotation sensor faces the sensormagnet 73 b in the axial direction (Z-axis direction). The rotationsensor 72 detects the position of the rotor depending on a change inmagnetic flux of the sensor magnet 73 b. Although not illustrated,according to the present exemplary preferred embodiment, three rotationsensors 72 preferably are disposed on, for example, the front surface 71b of the circuit board. Further, as the rotation sensor 72, for example,a hall device, etc., is used.

FIG. 2 is a partial cross-sectional view illustrating a portion of themotor 10. In more detail, FIG. 2 is a partially enlarged view of themotor shown in FIG. 1. FIG. 3 is a perspective view illustrating the busbar assembly 60. FIG. 4 is a plan view illustrating a bus bar assembly60.

The bus bar assembly 60 supplies a driving current from an externalpower source to the stator 40. As illustrated in FIGS. 1 to 4, the busbar assembly 60 preferably includes a bus bar holder 61, at least onebus bar 91, and a wiring member 92. In addition, in this preferredembodiment, the bus bar assembly 60 includes a plurality of the bus bars91.

The bus bar holder 61 is preferably defined by a holder made of resin.Preferably, a material forming the bus bar holder is an electricallyinsulating resin. The bus bar holder 61 holds the bus bar 91 and thewiring member 92. As illustrated in FIG. 1, a rear side (+Z side) of thebus bar holder 61 is accommodated in the cylindrical portion 22 a. Inthis preferred embodiment, the bus bar holder 61 is press-fitted intothe cylindrical portion 22 a. At least a portion of a front side (−Zside) of the bus bar holder 61 is accommodated in the bus bar assemblyinsertion portion 21 a of the housing 21.

As long as a material forming the bus bar holder 61 has an insulationproperty, any material may be used without being specially limited. Thebus bar holder 61 is preferably manufactured as a single monolithicmember by, for example, injection molding. As illustrated in FIGS. 3 and4, the bus bar holder 61 includes a main body portion 62, a connectorportion 63, a connection terminal holding portion 64, a rear bearingholding portion 65, connection portions 66 a, 66 b, 66 c, and 66 d, anda plurality of circuit board support portions 67.

As illustrated in FIGS. 1 and 3, the main body portion 62 preferably hasa cylindrical or substantially cylindrical shape enclosing the centeraxis J in the circumferential direction (θZ direction). The main bodyportion 62 includes an opening 62 a at the rear side (+Z side) thereof.The main body portion 62 includes an inner surface 62 b of a main bodyportion, a rear surface 62 c of the main body portion located at therear side, and an outer surface 62 d of the main body portion. A rearsurface 62 c of the main body is preferably provided with a grooveportion 62 f. The groove portion 62 f is provided along the contour ofthe main body portion 62 enclosing the opening 62 a. A rear side O-ring82 is fitted into the groove portion 62 f. As illustrated in FIG. 3, thefront side (−Z side) of the outer surface 62 d of the main body portionis provided with an O-ring holding portion 62 e. As illustrated in FIG.1, the front side O-ring 81 is fitted into the front side O-ring holdingportion 62 e. Further, an air gap is preferably housed within the mainbody portion 62 at a position radially outward from an end of thecircuit board 71 and between the circuit board 71 and an inner surfaceof the main body portion.

As illustrated in FIGS. 3 and 4, the main body portion preferablyincludes an arc portion 68 a and a connector connection portion 68 b. Asillustrated in FIG. 4, in this preferred embodiment, the shape of across section (XY cross-section) perpendicular to the center axis J ofthe arc portion 68 a and the shape of a plane view (XY plane view) is anarc shape concentric with the rear bearing holding portion 65.Preferably, a central angle of the arc shape may be φ240° or higher, forexample. As illustrated in FIG. 1, in this preferred embodiment, the arcportion 68 a is preferably press-fitted into the cylindrical portion 22a of the cover 22.

As illustrated in FIGS. 3 and 4, the connector connection portion 68 bis a portion connected to the connector portion 63. The connectorconnection portion 68 b is connected to both ends of the arc portion 68a. The connector connection portion 68 b protrudes toward the connectorportion 63 (+_X side). The rear bearing holding portion 65 is disposedin the main body portion 62 along the radial direction. The rear bearingholding portion 65 holds the second bearing 52.

As illustrated in FIG. 4, the connection portions 66 a, 66 b, 66 c, and66 d connect the main body portion 62 to the rear bearing holdingportion 65 disposed in the main body portion 62. The connection portions66 a-66 d are positioned at the circumference of the rear bearingholding portion 65 while being spaced apart from each other at equal orsubstantially equal intervals along the circumferential direction.

Gaps 66 e, 66 f, 66 g, and 66 h are provided among the connectionportions 66 a-66 d neighboring with each other in the circumferentialdirection. That is, gaps 66 e, 66 f, 66 g, and 66 h are provided betweenthe rear bearing holding portion 65 and the main body portion 62. Thegap 66 e is defined by the connection portion 66 a, the connectionportion 66 b, the main body portion 62, and the rear bearing holdingportion 65. The gap 66 f is defined by the connection portion 66 b, theconnection portion 66 c, the main body portion 62, and the rear bearingholding portion 65. The gap 66 g is defined by the connection portion 66c, the connection portion 66 d, the main body portion 62, and the rearbearing holding portion 65. The gap 66 h is defined by the connectionportion 66 d, the rear bearing holding portion 65, the connectionportion 66 a, the connection terminal holding portion 64, and the mainbody portion 62.

In a plane view, the position of the gap 66 e is a position includingcoil connection portions 91 a and 91 b to be described later. In a planeview, the position of the gap 66 f is a position including coilconnection portions 91 c and 91 d to be described later. In a planeview, the position of the gap 66 g is a position including coilconnection portions 91 e and 91 f to be described later. In a planeview, the position of the gap 66 h is a position including a circuitboard connection terminal 95 to be described later. In a plane view, theappearance of the gap 66 h is a rectangular or substantially rectangularshape.

At least one circuit board support portion 67 protrudes from the surfaceof the rear side (+Z side) of the rear bearing holding portion 65 towardthe rear side. In the example illustrated in FIG. 4, three circuit boardsupport portions 67 preferably are disposed on the surface of the rearside of the rear bearing holding portion 65. The circuit board supportportion 67 supports the circuit board 71 at the end of the rear side.

The connector portion 63 is a portion connected to external power supply(not shown). The connector portion 63 preferably has a cylindrical orsubstantially cylindrical shape. The connector portion 63 preferably hasa rectangular or substantially rectangular parallelepiped shape. Theconnector portion 63 extends from a portion of the outer surface of theconnector connection portion 68 b to the radially outer side (+X side)of the center axis J. The connector portion 63 has an opening at theradially outer side (+X side). That is, the connector portion 63protrudes from the main body portion 62 toward the radially outer sideof the center axis J. As can be seen from FIG. 1, the entirety of theconnector portion 63 preferably is exposed outside the cover 22.

As illustrated in FIG. 1, the connector portion 63 includes an opening63 a for a power supply opened toward one side (+X side) disposed in alongitudinal direction of the bus bar holder 61. A bottom surface of thepower-supply opening 63 a is provided with the bus bar 91 and anexternal power-supply connection terminal 94 to be described later. Thebus bar 91 and the external power-supply connection terminal 94protrudes from the bottom surface of the power-supply opening 63 atoward one side (+X side) disposed in the longitudinal direction of thebus bar holder 61.

As illustrated in FIGS. 2 to 4, the connection terminal holding portion64 has a rectangular or substantially rectangular parallelepiped shape.The connection terminal holding portion 64 protrudes toward the radiallyinner side from the inner surface 62 b of the main body portion 62. Inmore detail, as illustrated in FIG. 4, the connection terminal holdingportion 64 extends from the inner surface of the connector connectionportion 68 b in the direction (−X direction) opposite to the directionin which the connector portion 63 extends. Accordingly, at least aportion of the connection terminal holding portion 64 overlaps with theconnector portion 63 in the radial direction.

The connection terminal holding portion 64 includes an inner surface 64a of the holding portion in the radial direction. The end of the rearside (+Z side) at the holding-portion inner surface 64 a is located atthe front side (−Z side) ahead of the circuit board rear surface 71 a.The connection terminal holding portion 64 has the holding portion rearsurface 64 b at its rear side. In this preferred embodiment, theentirety of the holding portion rear surface 64 b preferably is parallelor substantially parallel to an XY plane. The end of the rear side ofthe connection terminal holding portion 64 is located at the front sideahead of the circuit board rear surface 71 a. That is, the holdingportion rear surface 64 b is located at the front side ahead of thecircuit board rear surface 71 a. In addition, the holding portion rearsurface 64 b is located at the front side ahead of the rear surface 62 cof the main body portion.

As illustrated in FIG. 2, an air gap AR1 is constructed at the rear side(+Z side) of the connection terminal holding portion 64. The air gap AR1is disposed between the circuit board 71 and the inner surface 62 b ofthe main body portion. In more detail, the air gap AR1 is disposedbetween the circuit board 71 and the inner surface of the connectorconnection portion 68 b in the inner surface 62 b of the main bodyportion.

The bus bar 91 is a thin plate-shaped member made of an electricallyconductive material (for example, metal, etc.). The bus bar 91 isdirectly or indirectly electrically connected to the stator 40. Thedriving current is supplied from external power supply or the like tothe stator 40 through the bus bar 91. Although not shown in thedrawings, according to this preferred embodiment, the plurality of busbars 91 is mounted to the stator 40. For example, if the motor is athree-phase motor, at least three bus bars 91 are mounted to the stator40. In addition, according to a difference in coil wiring methods, thenumber of bus bars 91 may be changed to, for example, 4 or higher. Eachbus bar 91 is disposed in the bus bar holder 61. One end of the bus bar91 protrudes from the bottom surface of the power-supply opening 63 a.One end of the bus bar 91 is exposed outside the cover 22. For example,the external power supply is connected to one end of the bus bar 91exposed outside the cover 22.

As illustrated in FIG. 4, the plurality of bus bars 91 include coilconnection portions 91 a, 91 b, 91 c, 91 d, 91 e, and 91 f. The coilconnection portions 91 a-91 f are disposed at other ends of theplurality of bus bars 91. The coil connection portions 91 a-91 fprotrude from the inner surface 62 b of the main body portion. In moredetail, the coil connection portions 91 a-91 f preferably protrude fromthe inner surface of the arc portion 68 a of the main-body-portion innersurface 62 b toward the radially inner side.

As illustrated in FIG. 1, the end of the rear side (+Z side) of the coilconnection portion 91 c is located at the rear side ahead of the circuitboard front surface 71 b. At least a portion of the coil connectionportion 91 c overlaps with the circuit board 71 in the radial direction.The coil connection portion 91 c is electrically connected to the coil43 through a connection member (not shown). Accordingly, the bus bar 91is electrically connected to the stator 40. The above-mentionedpreferred embodiment has disclosed only the coil connection portion 91 cfrom among the coil connection portions 91 a, 91 b, 91 c, 91 d, 91 e,and 91 f. However, in the above-mentioned description, the coilconnection portions 91 a, 91 b, and 91 d-91 f may be identical instructure to the coil connection portion 91 c, and as such a detaileddescription thereof will herein be omitted.

As illustrated in FIG. 2, the wiring member 92 is fixed to the bus barholder 61. That is, a portion of the wiring member 92 is preferablyembedded within the bus bar holder 61. The wiring member 92 electricallyconnects the external power supply (not shown) to the circuit board 71.The wiring member 92 includes the external power-supply connectionterminal 94 and the circuit board connection terminal 95. The externalpower-supply connection terminal 94 and the circuit board connectionterminal 95 are exposed from the bus bar holder 61. Further, at leastone portion of the wiring member 92 other than the external power-supplyconnection terminal 94 is preferably located closer to the cover 22 thanthe external power-supply connection terminal 94 is. For example, acircuit board connection terminal 95 is preferably located closer to thecover 22 than the external power-supply connection terminal 94 is.

The external power-supply connection terminal 94 is disposed in theconnector portion 63. The external power-supply connection terminal 94protrudes from the bottom surface of the power-supply opening 63 a. Theexternal power-supply connection terminal 94 is electrically connectedto the external power supply (not shown).

The circuit board connection terminal 95 is located at the front side(−Z side) ahead of the end of the rear side (+Z side) of the main bodyportion 62, such that the circuit board connection terminal 94 is fixedto the connection terminal holding portion 64. That is, in thispreferred embodiment, the circuit board connection terminal 95 islocated at the front side (−Z side) ahead of the rear surface 62 c ofthe main body portion, such that the circuit board connection terminal95 is fixed to the connection terminal holding portion 64. The circuitboard connection terminal 95 protrudes from the front end of theradially inner side of the connection terminal holding portion 64. Thatis, as illustrated in the example of FIG. 2, the circuit boardconnection terminal 95 protrudes from the holding portion inner surface64 a. Further, a portion of the circuit board 71 is preferably locatedto extend closer to the external power-supply connection terminal 94 ina radial direction than a portion of the circuit board connectionterminal 95 is.

The circuit board connection terminal 95 preferably includes a firstterminal portion 95 a, a second terminal portion 95 b, a third terminalportion 95 c, a fourth terminal portion 95 d, and a plate-shaped portion95 e. The first terminal portion 95 a protrudes toward the radiallyinner side from the holding portion inner surface 64 a. The firstterminal portion 95 a is located at the outside of the radial directionahead of the circuit board 71. According, as shown in FIG. 2, thecircuit board connection terminal 95 preferably includes a bent portionwhich is bent at or almost at a right angle.

The second terminal portion 95 b extends from the end of the inner sideof the radial direction of the first terminal portion 95 a toward therear side (+Z side). The second terminal portion 95 b extends to afurther rear side ahead of the circuit board rear surface 71 a. Thethird terminal portion 95 c extends from the end of the rear side (+Zside) of the second terminal portion 95 b toward the radially innerside. The fourth terminal portion 95 d extends from the third terminalportion 95 c to the front side (−Z side).

The plate-shaped portion 95 e extends from the end of the front side ofthe fourth terminal portion 95 d toward the radially inner side. Theplate-shaped portion 95 e is disposed at the end of the radially innerside of the circuit board connection terminal 95. The plate-shapedportion 95 e includes a connection surface 95 f at the front side. Theconnection surface 95 f is parallel or substantially parallel to thecircuit board rear surface 71 a. The connection surface 95 f contactsthe circuit board rear surface 71 a. Although not shown in the drawings,the plate-shaped portion 95 e is preferably fixed to the circuit board71 by, for example, soldering. Therefore, the circuit board connectionterminal 95 is electrically connected to the circuit board 71. That is,the wiring member 92 is electrically connected to the circuit board 71.

In this preferred embodiment, as illustrated in FIG. 4, in thecircumferential direction (θZ direction) of the center axis J, theposition of the circuit board connection terminal 95 is different fromthose of the coil connection portions 91 a-91 f of the bus bar 91.

As illustrated in FIG. 1, the front side O-ring 81 is disposed in thehousing 21. The front side O-ring 81 is fixed to the O-ring holdingportion 62 e of the bus bar holder 61. The front side O-ring 81 contactsthe inner surface of the housing 21 and the outer surface of the mainbody portion 62 over the circumference. That is, the front side O-ring81 contacts the main body portion 62 and the housing 21 over thecircumference. Stress generated from the inner surface of the bus barassembly insertion portion 21 a is loaded on the front side O-ring 81.

The rear side O-ring 82 is disposed in the cover 22. The rear sideO-ring 82 is fitted into the groove portion 62 f. The cover 22, to bedescribed later, includes a cover front surface 22 c at the front side(−Z side) of the cover portion 22 b. The entire circumference of therear side O-ring 82 contacts the cover front surface 22 c, to bedescribed later. Stress generated from the cover front surface 22 c isloaded on the rear side O-ring 82.

In this preferred embodiment, the front side O-ring 81 and the rear sideO-ring 82 are preferably made of, for example, resin including siliconrubber or the like. If the O-rings 81 and 82 are made of silicon rubber,the front side O-ring 81 and the rear side O-ring 82 are preferablymanufactured by, for example, machining elongated silicon rubber havinga round cross section in a ring shape. However, a configuration and amaterial of the front side O-ring 81 and the rear side O-ring 82 are notlimited thereto.

The cover 22 is attached to the rear side (+Z side) of the housing 21. Amaterial of the cover 22 is preferably, for example, metal. In moredetail, as the material of the cover 22, for example, aluminum or aniron alloy such as SUS is used. As described above, the cover 22includes a cylindrical portion 22 a, a cover portion 22 b, a cover frontsurface 22 c, and a rear side flange portion 24.

The cylindrical portion 22 a is opened toward the front side (−Z side).The cylindrical portion 22 a encloses the bus bar assembly 60 from theradially outer side of the center axis J. In more detail, thecylindrical portion 22 a encloses the end of the rear side (+Z side) ofthe main body portion 62 from the radially outer side of the center axisJ. In other words, at least a portion of the end of the rear side (+Zside) of the main body portion 62 is disposed in the cylindrical portion22 a. The cylindrical portion 22 a is connected to the end of the rearside (+Z side) of the bus bar assembly insertion portion 21 a throughthe front side flange portion 23 and the rear side flange portion 24.

The cover portion 22 b is connected to the end of the rear side (+Zside) of the cylindrical portion 22 a. In this preferred embodiment, thecover portion 22 b preferably has a plate shape. The cover portion 22 bpreferably includes the cover front surface 22 c at the front side (−Zside). The cover portion 22 b closes the opening 62 a, to be describedlater. The cover front surface 22 c contacts the entire circumference ofthe rear side O-ring 82. Therefore, the cover 22 indirectly contacts themain body rear surface 62 c through the rear side O-ring 82 over acircumference of the opening 62 a.

The rear side flange portion 24 extends from the end of the front side(−Z side) of the cylindrical portion 22 a toward the radially outerside. At least a portion of the front side flange portion 23 and atleast a portion of the rear side flange portion 24 are bonded to eachother while overlapping with each other, such that the housing 21 isbonded to the cover 22.

For example, the external power supply is connected to the motor 10through the connector portion 63. The bus bar 91 protrudes from thebottom surface of the power-supply opening 63 a. The connected externalpower supply is electrically connected to the bus bar 91 and the wiringmember 92. Therefore, the driving current is supplied from the externalpower supply to the coil 43 and the rotation sensor 72 through the busbar 91 and the wiring member 92. The rotation sensor 72 detects themagnetic flux of the rotor magnet. The driving current supplied to thecoil 43 is controlled depending on the rotating position of the rotor 30calculated based on, for example, the detected magnetic flux of therotor magnet. When the driving current is supplied to the coil 43, amagnetic field is generated in the coil 43. In other words, when thedriving current is supplied to the coil 43, a torque is generatedbetween the rotor 30 and the stator 40. With this torque, the rotor 30having the shaft 31 rotates. By doing so, the motor 10 obtains arotational driving force.

In this preferred embodiment, the rear side O-ring 82 is disposed in themain body rear surface 62 c. In addition, the cover 22 indirectlycontacts the main body rear surface 62 c through the rear side O-ring82. That is, the rear side O-ring 82 is disposed between the cover 22and the bus bar holder 61. Therefore, spacing between the cover 22 andthe bus bar holder 61 is sealed. As a result, water, oil, etc., may beprevented from flowing into the motor 10.

In addition, the end of the rear side at the holding portion innersurface 64 a is located at the front side ahead of the circuit boardrear surface 71 a. Therefore, at the radially outer side of the circuitboard 71, the air gap AR1 is defined in the connection terminal holdingportion 64. The air gap AR1 is defined between the circuit board 71 andthe main body portion 62. Therefore, when the circuit board connectionterminal 95 of the wiring member 92 is connected to the circuit board71, the main body portion 62 may be prevented from being deformed byheat, such as heat produced during soldering. Accordingly, theabove-mentioned preferred embodiment significantly reduces or preventsdeterioration of sealability between the cover 22 and the bus bar holder61 sealed by the rear side O-ring 82.

The circuit board connection terminal 95 protrudes from the holdingportion inner surface 64 a toward the radially inner side. Therefore, aradial distance between the circuit board connection terminal 95 and themain body portion 62 may increase. As a result, deformation of the mainbody portion 62 caused by heat, such as heat produced during soldering,is able to be further reduced or prevented. In addition, according tothis preferred embodiment, the circuit board connection terminal 95 maynot be located in the air gap AR1. Therefore, the circuit boardconnection terminal 95 is easily connected to the circuit board 71. Inaddition, the wiring member 92 may preferably be constructed in a mannerthat the circuit board connection terminal 95 is able to be linearlyconnected to the external power-supply connection terminal 94. As aresult, the wiring member 92 is able to be easily manufactured.

The holding portion rear surface 64 b may be located at the front sideahead of the circuit board rear surface 71 a. Therefore, a numericalvalue of the radial direction of the air gap AR1 may be furtherincreased. Therefore, the above-mentioned preferred embodiment is ableto further reduce or prevent deformation of the bus bar holder 61 whenthe circuit board connection terminal 95 is connected to the circuitboard 71.

The holding portion rear surface 64 b is located at the front side aheadof the main body rear surface 62 c. Therefore, as illustrated in FIGS. 1and 2, the circuit board 71 may be disposed in the main body portion 62.As a result, the cover portion 22 b located at the rear side of the mainbody portion 62 may have a plate shape, for example. In addition,spacing between the main body portion 62 and the cover 22 may be sealedby, for example, the rear side O-ring 82. Therefore, the above-mentionedpreferred embodiment may easily and simply perform shaping of the cover22, and may improve sealability between the cover 22 and the bus barholder 61.

The ends of the rear side of the coil connection portions 91 a-91 f arepreferably located at the rear side ahead of the circuit board frontsurface 71 b. Therefore, the end of the rear side of the coil connectionportions 91 a-91 f is located at the rear side ahead of the circuitboard support portion 67 supporting the circuit board 71. Therefore,from the side of the opening 62 a, the coil connection portions 91 a-91f may be easily connected to the coil 43.

At least a portion of the coil connection portions 91 a-91 f overlapwith the circuit board 71 in the radial direction, such that a numericalvalue of the axial direction of the motor 10 is able to be reduced.

The circuit board connection terminal 95 preferably includes theplate-shaped portion 95 e including the connection surface 95 f. Theconnection surface 95 f is in contact with the circuit board rearsurface 71 a. Therefore, according to this preferred embodiment, thecontact region between the circuit board connection terminal 95 and thecircuit board 71 may be increased in size, and the circuit boardconnection terminal 95 and the circuit board 71 may be stably fixed.

The position of the circuit board connection terminal 95 is different inposition from the coil connection portions 91 a-91 f in thecircumferential direction centered on the center axis J. Therefore, whenthe circuit board connection terminal 95 is connected to the circuitboard 71 and the coil connection portions 91 a-91 f are connected to thecoil 43, mutual interference between the circuit board connectionterminal 95 and the coil connection portions 91 a-91 f is able to bereduced or prevented, resulting in facilitation of each connection.

The rear side O-ring 82 is disposed on the main body rear surface 62 c,such that sealability between the cover 22 and the bus bar holder 61 isable to be improved.

In addition, the following constituent elements can also be applied topreferred embodiments of the present invention.

In the above-mentioned description, the entirety of the holding portionrear surface 64 b preferably is located at the front side ahead of thecircuit board rear surface 71 a. However, the position of the holdingportion rear surface 64 b is not limited to the above-mentionedposition. In various preferred embodiments, other portions of theholding portion rear surface 64 b may be located at the same position asthat of the circuit board rear surface 71 a in the axial directionwithin the range in which the end of the rear side of the holdingportion rear surface 64 b is located at the front side ahead of thecircuit board rear surface 71 a, and may also be located at the rearside ahead of the circuit board rear surface 71 a.

The holding portion rear surface 64 b may be an inclined plane or acurved surface with respect to the radial direction, for example.

The circuit board connection terminal 95 may also protrude from theremaining portions other than the holding portion inner surface 64 a. Inthis preferred embodiment, for example, the circuit board connectionterminal 95 may also protrude from the holding portion rear surface 64b.

The circuit board rear surface 71 a may also be located at the rear sideahead of the main body portion 62. According to this preferredembodiment, in the radial direction, the circuit board rear surface 71 adoes not overlap with the main body portion 62. Therefore, theabove-mentioned preferred embodiment is able to further reduce orprevent deformation of the main body portion 62 affected by heat whenthe circuit board connection terminal 95 is connected to the circuitboard rear surface 71 a.

In the axial direction, the holding portion rear surface 64 b may alsobe identical in position to the main body rear surface 62 c. By thisstructure, the structure in which the circuit board 71 is located at therear side ahead of the main body portion 62 is able to be easily appliedto the preferred embodiment.

In the above-mentioned description, the circuit board 71 is located atthe rear side of the shaft 31. However, the position of the circuitboard 71 is not limited thereto. For example, a through-hole may bedefined in the circuit board 71, and the shaft 31 may be inserted intothe through-hole. In this case, the end of the rear side of the shaft 31preferably protrudes toward the rear side of the circuit board 71.

In the above-mentioned description, the rear side O-ring 82 preferablyis a member that seals a gap between the cover 22 and the bus bar holder61. However, according to this preferred embodiment, the scope of themember that seals the gap between the cover 22 and the bus bar holder 61is not limited to the above-mentioned member. For example, a liquidgasket or the like may be used in the sealing member. Similarly, thescope of a member that seals a gap between the housing 21 and the busbar holder 61 is not limited to the above-mentioned member, and a liquidgasket and the like may also be used in the sealing member.

If the liquid gasket is used to seal spacing between the cover 22 andthe bus bar holder 61, the cover 22 may directly contact the main bodyrear surface 62 c over a circumference of the opening 62 a. That is,according to this modified preferred embodiment, the cover 22 maydirectly or indirectly contact the main body rear surface 62 c over acircumference of the opening 62 a.

The motor according to this modified preferred embodiment may be, forexample, the structure of FIG. 5. FIG. 5 is a partially enlargedcross-sectional view of the motor 110 according to another preferredembodiment of the present invention. In the following description, thesame constituent components as those of the above-mentioned preferredembodiments are denoted with the same reference numbers, and thereforethe description thereof may be omitted.

As illustrated in FIG. 5, the motor 110 preferably includes a bus barassembly 160. The bus bar assembly 160 is provided with a bus bar holder161. The bus bar holder 161 includes a connection terminal holdingportion 164.

The connection terminal holding portion 164 preferably includes aholding portion rear surface 164 b located at the rear side (+Z side).At least one rib 169 is disposed in the holding portion rear surface 164b. The rib 169 protrudes from the holding portion rear surface 164 b tothe rear side at the end of the radially inner side of the holdingportion rear surface 164 b.

The end of the rear side of the rib 169 is located at the front side (−Zside) ahead of the circuit board rear surface 71 a. That is, the end ofthe rear side at the holding portion inner surface 164 a including theradially inner surface of the rib 169 is located at the front side aheadof the circuit board rear surface 71 a. Accordingly, in the radialdirection, an air gap AR2 is constructed in the connection terminalholding portion 164 of the circuit board 71. Other constituent elementsof the motor 110 are identical to those of the motor 10 shown in FIGS. 1to 4, and therefore the description thereof will be omitted.

In accordance with the above-mentioned structure, the rib 169 is locatedin the connection terminal holding portion 164, resulting in increasedrigidity of the connection terminal holding portion 164. Therefore, thebus bar holder 161 is able to be prevented from being deformed byexternal force or the like.

While preferred embodiments of the present invention have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing from the scopeand spirit of the present invention. Further, features of theabove-described preferred embodiments and the modifications thereof maybe combined appropriately as long as no conflict arises. The scope ofthe present invention, therefore, is to be determined solely by thefollowing claims.

What is claimed is:
 1. A motor, comprising: a rotor including a shaftwith a center on a center axis extending in one direction from a firstside of the motor to a second side of the motor; a stator enclosing therotor and rotating the rotor about the center axis; a cylindricalhousing holding the stator; a bus bar assembly including a surfacefacing the first side of the motor and opposing the housing; and acircuit board disposed in the bus bar assembly and opposing an innersurface of the bus bar assembly in a radial direction which isperpendicular to the center axis; wherein the bus bar assembly includes:a wiring member electrically connecting an external power supply to thecircuit board; and a bus bar holder that holds the wiring member; thebus bar holder includes: a cylindrical main body portion; and aconnector portion that protrudes from the main body portion toward aradially outer side of the center axis; the wiring member includes: anexternal power-supply connection terminal provided in the connectorportion to be electrically connected to the external power-supply; and acircuit board connection terminal that is electrically connected to thecircuit board; and at least one other portion of the wiring member islocated closer to the second side of the motor in the one direction thanthe external power-supply connection terminal.
 2. The motor according toclaim 1, wherein at least a portion of the circuit board connectionterminal is located closer to the second side of the motor in the onedirection than the external power-supply connection terminal.
 3. Themotor according to claim 2, wherein a portion of the circuit boardextends closer to the external power-supply connection terminal in theradial direction than a portion of the circuit board connectionterminal.
 4. The motor according to claim 1, wherein an air gap ishoused within the cylindrical main body portion at a position radiallyoutward from an end of the circuit board and between the circuit boardand an inner surface of the main body portion.
 5. The motor according toclaim 1, further comprising: a first bearing located at a first side ofthe stator in the one direction and supporting the shaft; a secondbearing located at a second side of the stator opposite to the firstside of the stator and supporting the shaft.
 6. The motor according toclaim 1, wherein at least a portion of the circuit board connectionterminal includes a bent portion which is bent at or almost at a rightangle.
 7. The motor according to claim 1, further comprising a sensormagnet facing the circuit board.
 8. The motor of claim 1, wherein thecircuit board connection terminal includes: a first portion protrudingout from the cylindrical main body portion; and a second portion locatedinside the cylindrical main body portion.
 9. The motor of claim 1,wherein the surface of the second side of the circuit board is locatedat the second side of the external power-supply connection terminal. 10.The motor of claim 1, wherein: at least a portion of the bus baroverlaps with the circuit board in the radial direction.
 11. The motorof claim 1, wherein the circuit board connection terminal and at least aportion of the bus bar are located at different positions in acircumferential direction of the center axis.
 12. The motor of claim 1,wherein: the circuit board connection terminal includes a flatplate-shaped portion; the plate-shaped portion includes a connectionsurface parallel or substantially parallel to the surface of the secondside of the circuit board; and the connection surface is in contact withthe surface of the second side of the circuit board.
 13. The motor ofclaim 1, wherein the surface of the second side of the connectionterminal holding portion is provided with a rib.